The present invention relates generally to a suspension module for use with an independent suspension preferably including a pair of pivotal semi-trailing arms each having an airbag support which supports an airbag positioned between the semi-trailing arms and a subframe.
Heavy vehicles, such as trucks, typically utilize a suspension system to provide a smooth and comfortable ride. A suspension system commonly includes a pair of parallel suspension arms which are pivotally attached to generally parallel frame rails of the vehicle chassis. An airbag is attached to the frame rail to compensate for various wheel load conditions. The suspension system translates road forces imparted to the wheels into rotational movement of the suspension arms relative to the frame rail. The rotational movement of the suspension arm is cushioned by the airbags.
In one prior art commercial vehicle system, the airbags are mounted to a transverse beam extending across the ends of the suspension arms and supported on the frame rails. This prior art system is not an independent suspension.
In another prior art independent suspension system, the airbags are mounted to the suspension arms over the axle centerline and directly attached to the frame rails of the vehicle chassis. This positioning of the airbags over the axle centerline in an independent suspension makes the fitting of the suspension system under the frame rail of the vehicle chassis difficult. This problem increases when double tires are employed and as vehicle weight increases, requiring larger airbags.
Finally, coil spring positioned over the axle centerline and attached directly to the frame have been employed in passenger vehicles.